Diaphragm walls have been known for a long time. The method for making them is always substantially identical: an excavation with a profile corresponding to that of the wall that one desires to obtain is formed in the ground. Stability of the excavation during the drilling operation is obtained by means of filling it with a liquid called “mud,” generally based on bentonite. This mud forms a sealed deposit on the walls of the excavation that prevents it from percolating into the ground and prevents collapse of the walls. When the depth of the excavation has reached the desired level, the excavation is progressively filled with concrete, beginning below the mud in the bottom of the excavation.
In service, a diaphragm wall is subjected to loads, and particularly to tension forces, which can cause it to crack, and in more serious cases can fracture the concrete. The work is then in danger of deforming, threatening the integrity of adjoining structures.
One means of limiting cracking consists of increasing the strength of the work by increasing its dimensions. But this brings about an increase in the resources and the space needed for making it.